I have this fascination with kit-cars, and my favorite one right now is the Model T. Specifically I like the kits from Total Performance. I would do a ’27 T-bucket, open top, modern tires (175 wide in front, 245 rear) and use a Harley V-Rod engine (125hp/86tq). That would give the car plenty of pep being that it should weigh in at 1,200lbs or so. Only 9.6 lbs per hp, better than a 2011 Taurus SHO, not quite as good as a 2011 Mustang GT.
Something like this would be nice: